Itaconic acid, an unsaturated C5 dicarboxylic acid produced by various microorganisms, can be used as a precursor of many industrially relevant compounds in chemical and pharmaceutical industries. It is especially of interest for the production of polymers, because of its potential as a substitute for acrylic and methacrylic acid used for the production of plastics. Acrylic and methacrylic acid are severely irritating and corrosive to the skin and the resiratory tract Itaconinc acid on the other hand is non toxic and readily biodegradable and for these reasons the need for itaconic acid in the above-mentioned productions is expected to increase.
Current fermentation processes for the production of itaconic acid from sugar are executed aerobically using oxygen as the terminal electron acceptor. The productivity of aerobic processes is usually low (<1 g/l/h) and is determined by the oxygen transfer rate and/or the cooling capacity required for dissipating the heat that is generated. The yield of aerobic processes is limited, because the substrate can be completely oxidized by respiration. Moreover respiration generates a lot of metabolic energy, resulting in the conversion of substrate into microbial biomass, which also lowers the product yield.
Accordingly, there is a need to further improve itaconic acid production processes so that economically viable, large scale production may be achieved in industrial bioreactors.